Combination electric switch and variable resistor



March 15, 1960 w A, BARDEN ETAL 2,929,040

COMBINATION ELECTRIC SWITCH AND VARIABLE RESISTOR Filed June 12, 1958 3 Sheets-Sheet 1 77 75 :N71 -^85 '04 i il 7;

JMJ/wv w Wayne A..Earden ervm El..Az-zsman March 15, 1960 w A, BARDEN ETAL 2,929,040'

COMBINATION ELECTRIC SWITCH AND VARIABLE RESISTOR Filed June 12, 1958 3 Sheets-Sheet 2 March.15, 1960 w, A, BARDEN ETAL 2*,9295040 COMBINATION ELECTRIC SWITCH AND VARIABLE RESISTOR Filed June 12, 1958 3 Sheets-Sheet 3 COMBINATION ELECTRIC SWITCH AND VARIABLE RESISTOR Wayne A. Barden and Mervin B. Arisman, Elkhart, Ind., assignors to Chicago Telephone Supply Corporation, Elkhart, Ind., a corporation of Indiana Application June 12, 1958, Serial No. 741,504

l 15 Ciaims. (Cl. 338-172) This invention relates to combination electric circuit controlling instrumentalities of the type which comprise a switch and a variable resistor, and has more particularV reference to a miniaturized combination electrical control instrumentality adapted for use in conjunction with transistorized appliances, especially those employing printed circuits.

The great savings in space afforded by the use of printed circuits and especially those incorporating transistors has led to an ever increasing demand for complementing miniaturized controls. In this respect, it is the main objective of this invention to provide a miniaturized combination electric switch and variable resistor by which full advantage of the space saving features ofA transistors and printed circuitry may be achieved.

While many existing combination controls of the type here referred to feature compactness and small overall dimensions, they have not proved adaptable to miniaturi- Zation to the extremely small dimensions necessary to complement printed circuits with transistors. It is a requisite in such controls-that they be designed for higher ratings and heat capacities, along with overall smallness of their component parts. While the compo nents of some existing combination electric switches and variable resistors might be scaled down to a certain eX- tent, electrical clearances must remain at established safe limits. Heretofore, these limits have precluded scaling down the components of combination controls of existing designs to such small dimensions as to achieve true miniaturization of the controls.

It is another objective of this invention, therefore, to provide a combination electric switch and variable resistor having components of new and improved design which can be made small enough to achieve the desired miniaturization of the control without departure from the established electrical limits and clearances.

A further purpose of this invention is to provide a miniaturized combination electric switch and variable resistor of the character described which is comprised of a minimum number of component parts.

Still another object of this invention resides in the provision of a miniaturized combination electric switch and variable resistor which is of sturdy construction and capable of a long and satisfactory life, and which incorporates components that are designed for ease of assembly and efficient manufacture at low cost.

With the above and other objects in view which will appear -as the description proceeds, this invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the herein disclosedv invention may be made as come within the scope ofthe claims.

The accompanying drawings illustrate one complete example of the physical embodiment of the invention constructed according to the best lmode so -far devised for variable resistor showing the base the practical application of the principles thereof, and in which:

Figure 1 is an enlarged longitudinal sectional view of the combination electric switchvand variable resistor of this invention;

Figure 1a is an elevational view of the combination control instrumentality shown in Figure l but illustrating the actual size thereof;

Figure 2 is an enlarged group perspective view of the thereof removed from the resistor housing; j i

Figure 3 is an enlarged group perspective view o f the combination control instrumentality viewed fromthc front and `with the switch housing detached; and

Figure 4 is an enlarged elevational view of a portionv of the instrumentality, a portion of vthe switchhousing being broken away to Aillustrate the switch mechanism therein.

Referring now more particularly to the accompanying drawings, wherein like reference characters have been applied to like parts throughout the views, the combina tion electric circuit controlling instrumentality of this invention comprises housing means generally designated 5 comprised of a front section or switch housing 6 and a rear section or variable resistor housing 7 secured to the back of the front housing section in coaxial relation therewith. Note that departure is made from most conventional combination electric, switch and variable resistors in that the front housing section 6 contains the switch mechanism 8, and the rear housing section 7 contains the variable resistor mechanism 9. Both the switch and variable resistor mechanisms, of course, are adapted to be controlled by a common operating shaft 10 extending rearwardly into the switch housing section 6 from its front.

The housing means 5 includes a side wall, transverse front and rear walls 11 and 12, and a transverse intermediate wall 13 substantially equidistant from the front and rear walls. Each of the housing sections 6 and 7 is comprised of a cuplike metal stamping having a flat forwardly facing bottom wall and a cylindrical side wall. The bottom wall 14 of the rear housing section 7 lies at against the rear of an insulating disc 15 that provides the switch base, and together therewith constitutes the intermediate wall 13 ofthe housing means. v

The cylindrical side wall 16 of the rear housing secf tion extends rearwardly from the bottom wall 14 and has its rim 17 in abutting engagement with the rear wall 12 of the housing means. The rear wall 12 is formed of insulating material and provides a base upon which the stator elements 18 of the variable resistor are mounted. It is secured in position covering the open rear of the cuplike variable resistor housing by means of a number of circumferentially spaced mounting tabs 20 on the side wall 16 projecting rearwardly from its rim through notches 21 in the edge portions of the rear wall and bent over upon the rear face of the rear wall as at 22.

The front wall 11 of the housing means provides the bottom of the cuplike switch housing 6, and the cylindrical side wall 24 of the latter projects rearwardly therefrom to have its rim 25 in abutting engagement with the forward face of the switch base 15. The side wall 24 of the switch housing also has a slightly smaller diameter than that of the side wall 16 of the variable resistor housing.

The two housing sections are secured together in coaxial end to end relation with the switch base 15 clamped be-` tween the bottom wall 14 of the rear housing section'anjd the rim 25 of the front housing section. For this pur pose circumferentially spaced mounting tabs 26 are pro: vided on the side wall 24 of the switch housing, the tabs projecting rearwardly from its rim through suitable vPatented Mar. 15, 19.6()

. notches 27 in the edges of the switch base and through perforations 28 in the bottom wall 14 of the rear housing section, and being bent inwardly over the rear face of l the lwall 14 as at 29. The apertures 28 in the bottom wall 14 of the rear housing section, of course, are located near the periphery thereof. Y

Y The stator elements 1S of the variable resistor are comprised of a collector ring 31 and an arcuate resistance strip 32 surrounding the collector ring in spaced concentricrrelation thereto. Both stator components are mounted at'against the forward face of the variable resistor base 12, and are coaxial with the two housing sections.

The variable resistor mechanism also lincludes a rotor which is comprised of a carrier 34 molded of insulating material, and a contactor generally designated iixcd to the rear .of the rotor. The `contactor carrier has a Substantially disclke body portion 36 having the s011- tactor V@i Yfixed to its liat rear face in a manner to be described later, and having a forwardly projecting stepped hub generally designated 37.

lhe intermediate hub portion 38 provides a journal which is rotatably received in a mainbearing hole 39 of substantially large diameter formed in the intermediate Wall 13 of the housing means. As will be apparent from Figure l, this bearing hole consists of coaxial holes of 'the samediameter in both the switch base 1S and the foremost axial position of the carrier in the variable i resistor housing. The smallest diameter hub portion 43 projects forwardly from the intermediate hub portion 38 into the interior of the switch housing 6 and it is formed with an axial thrust switch actuating cam 44 on itsside, adjacent to the rear of the switch compartment, to control the switch mechanism 8 in accordance with the. position of rotation of the contactor carrier.

Both the front and rear walls 11 and 12 of the housing means are provided with apertures 4S and 46, respectively, at their centers. The aperture 4.6 in the base 12 of the variable resistor provides a pilot bearing in which a journal 47 projecting from the rear of the contactor carrier is received to cooperate with the main bearing hole in the intermediate wall 13 in the provision 0f van exceptionally stable support for the rotor of the variable, resistor. The journal 47 projects from a slightly larger diameter boss 48 on the. rear of the contactor carrier, and this boss. bears against the collector ring 31 to hold, the .same against separation from the base 12. of

the. variable resistor, and in a fixed position defined by f the ,engagement of rearwardly extending locating tabs 49 on the periphery of the ring in apertures 49 in the base 12 With the construction. thus far described it will be appreciatedfthat the contactor carrier is constrained to rotation within the housing means, 'being held against sub4 stantially all axial motion by reason of the engagement of the Vboss .4,8 with the collector ring A3.1 at the rear of the carrier and the engagement. of the. front en'dof its largest. diameter hub portion 4l with the front wall 14- of the resistor housing. .Accordingly the disclike body portion 36 of the contactor carrier is at allV `times held at a fixed distance from the collector ring 31 and the resistance element 32, and this feature of the invention is utilized to assure proper tensioning of a plurality of spljingv fingers 5,0, 51 and 52 on. the.. contactor', and vengagement of'paddlesv or' contact portions 15th, 151, and 15,2 on their respective free ends with the. resistance ele ment and the collector ring under adequate contact pressure. The contact portions 150 and 151 of the 4Spring fingers 50 and 51 engage and ride upon the forwardly facing surface of the resistance element 32, while the contact'engaging portion 152 of the spring finger 52 engages and rides upon the forwardly facing surface of the collector ring 31.

The construction of the contactor 35 and Vthe manner in which it is secured to the rear of the contactor carrier 34 are also important features of this invention. Referring to Figure 2, it will be seen that the contactor, which is stamped and formed from sheet metal having good resiliency, has a body portion 54 located wholly to one side of the boss 48 on the rear of the carrier and which flatwise overlies and seats against the rear face of the disclike body 36 of the carrier. The body portion 54 of the contactor has a medial locating hole 55 therein to receive a protuberance 56 onthe rear of the carrier, and it is secured to the carrier by a pair of mounting tabs 58 bent forwardly from the o uter edge of its body portion and passing'through *suitable` notches 5? in Vthe periphery of Vthev disclike body 36 'ofthe'carricn the for? ward extremities ofthese tabs being bent inwardlyV over the front face of the disc 36 as at 6i). Attention is dil rected to thefact that the mounting tabs 5S are located equal distances from a plane containing the carrier axis and passing through the center of the protuberance 56, so as to be equidistant from the protuberance.

The opposite side of the contactor is cut out to provide the arcuate but oppositely curved outer spring fingers 'e'tl and 51 which emanate from areas of the body portion 54 adjacent to the securing tabs 5,8, and the inner spring finger 52 which emanates from the body portion 54 directly adjacent to the protuberance 56. The fingers Se and 51 extend around and overlie the outer portion of the carrier body 36 and their contact end portions 1541 and 151 closely radially overlap one another at the side of the carrier axis remote from the protuberance S6, behind a stop lug 62 formed on the carrier and projecting forwardly from the disclike body 36 thereof.

The inner spring nger 52 is also of arcuate configuration and it is substantially concentric to the outer finger 51. It curves around the boss 48 on the rear of the carrier, in radially spaced relation to the boss and to the adjacent outer finger 51, to have'its contact end portion 152 radially adjacent to but spaced inwardly from the contact end portions of the outer spring iingers.

All of the spring lingers, of course, are sprung rearwardly away from the body disc 36 of the carrier so that when the carrier assembly is installed in kthe housing means in the `manner described heretofore, the contact portions. of the Vfingers'will be flexed V*forwardly by their engagement with the collector ring and resistance path and thus held properly tensioned thereby. Y

The rotation stopv 62, which ,is shown at the top of the carrier in Figures 1 and 2, is engageable with either side of a cooperating stop 64 in the rear housing section formed as an indentation in the sidewall 1'6 thereof `adjacent to the bottom wall 14 of the resistor housing. Consequently with the positions of the parts as shown, the contactor carrier is approximately Onehalf way between its limits of rotation.

The collector ring 31, of course, has a central aperture 66 of the same size as the pilot and through which the' journal 47 onthe rear of the contactor carrier projects, and forms part of the Vpilot bearing. The collector ring, moreover, is formed with a terminal 67 which-is'Y integral therewith, and which comprises an elongated strip of metal joined at one end to `theperiphery ofthe .ring asat 68 and which is bent rearwardly and downwardly there;- from to. extend at an angle through a locating hole 69 .in the rear wall 12, to the rear of thehousing means. The outer end portion 7G, ofthe terminal is directedldownwardly so as to be located in parallel but offset relation tor the collector ring proper, and. it has a pointed end 71 to facilitate insertion into a hole 72. in a panel 73 yhaving circuit wiring printed thereon to enable the terminal to be soldered'to the wiring. The engagement of the inner end portion of the terminal 67 in the hole 69 thus4 may serve to hold the ring against rotation on the rear wall 12, but as noted previously, the tangs 49 fitting in the holes 49 of the rear wall also serve to locate and hold the collector ring in the proper position on the resistor base 12.

Terminal board extensions 75 and 76 on the register vbase 12 and the switch base 15 project downwardly therefrom beyond the side wall of the housing means to have their lower ends engage the upper surface of the printed circuit panel 73, to properly space the housing means of the combined control instrumentality from the panel and to locate the instrumentality with its axis parallel to the panel. Preferably the terminal board extension 76 has a single rounded downwardly projecting protuberance 77 on the medial portion of its lower edge to engage the upper face lof the panel 73, while the terminal board extension 75 is provided with a pair of such protuberances 78 located near its opposite side edges.

This in effect provides Va stable tripod support for the instrumentality.

The resistance element 32 surrounds the collector ring in spaced concentric relation thereto, and its ends are disposed at opposite sides of and closely adjacent to the hole 69 through which the terminal 67 of the collector ring passes. Extensions or legs 80 on the resistance element project downwardly therefrom along the front of the terminal board extension 75 to provide for securement of the element in place upon the variable resistor base, as by means of terminal members 81 clamped onto the terminal board extension as at 82. These terminal members have prongs 83 extending downwardly beyond the lower edge of the terminal board extension 75 for engagement in holes 84 in the printed circuit panel. The terminals 81, of course, are adapted to be soldered to the wiring printed on the panel to connect the resistance element in a circuit.

According to this invention the stepped hub of the contactor carrier 34 has an elongated axial bore 85 therein extending rearwardly from the outer or forward end of the smallest hub portion 43 to the disclike body 36 of the carrier. The bore has a drive socket at its inner end provided by diametrically opposite bosses S6 formed on the side walls of the bore and having parallel spaced apart flat surfaces 87 which in effect constitute driving abutments.

The operating shaft for the combined electric switch and variable resistor projects rearwardly through the aperture 45 in the front wall 11 of the instrumentality and into the switch compartment to be received in and supported by the bore 85 in the contactor carrier hub. The rear portion of the operating shaft terminates a short distance forwardly of the bottom of the bore 85 and it is broached to provide double atted surfaces 89 which are received in the drive socket and cooperate with the abutments or bosses 86 to constrain the carrier to rotate with the operating shaft. The forward end portion of the operating shaft extends a distance beyond the front of the housing means, as seen in Figure la, and it may have the usual control knob (not shown) attached thereto.

It is a feature of this invention that the aperture 45 in the front wall 11 of the instrumentality has a keyhole shape, with the small end 90 of the keyhole coaxial with the bearing hole 39 in the intermediate wall 13 of the housing means, and with the large end 91 of the keyhole eccentric to the axis of the operating shaft and of a size to permit endwise passage of the shaft therethrough. The small end 90 of the key hole has a diameter less than that of the operating shaft and it engages in a circumfere'ntial'groove 93 in the shaftin the assembled vconditionof the parts lshown best in Figure 1 to hold the shaft against axial motion relative to the housing means and to assure that any endwise thrust upon the shaft will be carried directly into the front wall 11 of Vthehoiising means.

Consequently, there is no possibility of rearward end' ing 45 is prevented, especially during assembly of the components of thc instrumentality, by retaining means 95 in the nature of a washer of insulating material on the shaft 10, inside the switch housing. The washer 95 has a central hole 96 of a size to snugly but rotatably receive'the operating shaft, and it is held against the bottom wall 11 of the switch housing by the small diameter hub portion 43 of the contactor carrier. It will be noted that the hub portion 43 of the carrier extends forwardly substantially entirely through the interior of the switch housing, to have its outer end in abutting relation with the washer 95 to hold the same confined between the end of the hub portion 43 and the wall 11.

The washer 95 has a diameter such that its periphery is contiguous to the inner surface of the side wall 24 of the switch housing, to thus coact with the side wall in holding the operating shaft against shifting in any lateral direction relative to the housing means. Preferably, the washer or shaft retainer 95 -is provided with a notch 97 in its periphery to receive an indentation 98 in the side wall 24 of the switch housing, adjacent to the bottom wall 11 thereof, so as to assure against any rotational displacement of the washer as a consequence of rotation of the operating shaft.

The switch mechanism in the front housing section 6 comprises stationary and movable contacts 100 and 101, respectively, mounted on the base 15 so as to be located in the rear portion of the switch compartment. The switch contacts are stamped from resilient sheet metal and the lower end of each is formed with a combined terminal and mounting portion 102 which flatwise overlies the front face of the terminal board extension 76. These terminal and mounting portions are elongated and substantially parallel to one another, and they extend along opposite side edge portions of the terminal board extension to be clamped thereto as at 103 near the lower edge of the extension, to thereby secure the contacts to the switch base. Prongs 104 on the terminal portions project downwardly beyond the lower edge of the terminal board extension for engagement in suitable holes 105 in the printed circuit panel 73 where they may be electrically joined by soldering with wiring printed on the panel.

The stationary contact 100 has a short, arcuate upper portion which is concentric to the axis of the carrier and which is disposed edgewise adjacent to one side of the hub portion 43 on the carrier, but spaced radially outwardly therefrom a distance to enable the switch operating cam 44 to clear it when the contactor carrier is in its switch off limit of rotation seen in Figure 4.

The short arcuate contact portion of the stationary contact 100 member at all times lies flat against the front face of the switch base 15, but the movable contact 101 has a long arcuate upper portion or blade which may be exed back and forth, toward and from the switch base. As seen best in Figure 3 the arcuate upper portion or blade of the movable contact has one end joined to its terminal portion 102 remote from the stationary contact, and it extends in a clockwise direction more than half way around the hub portion 43 of the carrier to have a V-shaped contact portion 106 on its free end overlying and cooperable with the arcuate portion 100 of the stationary contact.v The V-shaped contact portion 106 is deformed rearwardly out of the plane of the arcuate blade, to have its apex normally engage the stationary contact 100 under the spring pressure incidental to the .f7 tendency 1t-the., blade 't0 assume ,a position atwise against the switch base. i It is important to note that lthe free end portion of the movable contactor blade is widened in a radial direction so that it extends radially inwardly beyond the inner edge of the arcuate stationary contact, to enable it to be acted upon by the axial thrust cam 44 o n the carriera. Also, one leg of the V-shaped contact portion 106 provides an inclined carn 107 which projects forwardly and downwardly to be engaged by the switch actnating cam 44 during rotation of the contactor carrier towardthe switched' f position seen in Figure 4, to enable the contact portion ldd of the movable contact to be ca mrned or lifted off of the stationary contact to open the switch.

The switch actuating Cam 44 has arcuate surface ilS that lies in a plane Dnormal to the axis of rotation ofthe operating shaft and faces forwardly, upon which the V-shaped contact portion 106 vof the movable Contact rests in the'switch open position seen in Figure 4, to hold the Switch Contacts separated- AInitial Switch open: ing engagement between the switch actuating ca rn and the cam portion `1li/7 kon the free end of the movable contact, however, is established between a forwardly projecting crown `11.@9 on the switch actuating cam and the cam leg 107 of the movable contact. Consequently, during iinal rotationV of Vthe contactor carrier towardl the switch olf position seen in Figure 4, the crown rides under the apex of the contact portion 106 and exes the Contact blade forwardly a slight distance beyond that which it normally occupies in the switch olf position. As soon as the'crown v109v passes the apex of the contact portion 106, the contact blade snaps rearwardly to bring the apex of its contact portion onto the at surface 108 of the switch actuating cam, by the inherent resiliency in the arcuate portion of theblade. This action takes place with a pronounced click by which an operator of .the instrumentality is assured that the switch is open.

The provision of the kforwardly projecting crown i? on the switch actuating cam also provides assurance against accidental rotation of theY contactor carrier 34 and its cam in the direction of-switch closing motion, such as might be caused by vibration or the like. in such an event, the crown'109 might come into contact with the apex of the V-shaped contact portion 1.06, but the rearward Vbias of the contactV blade is adequate to hold the contacter carrier against further rotation in the switch closing direction.V

Ordinarily, the tripodal seating of the terminal board extensions 75 and 76 on the printed circuit panel 73, together Vwith the soldering 4of the terminal prongs in the apertures of the panel, are sufficient to adequately and firmly mount the combined switCl and variable resistor of this invention in place upon the panel. in electrical appliances snch as small portable radio receivers or the like, additional support for the control instrumentality may be had through the provision of sccuring Vears 111 struck forwardly from the Afront wall 11 of the instrumentality and projectable through suitable apertures in the chassis (not shown) of the receiver to be bent down over'the front face of the panel.

From the foregoing description, together with the accompanying drawings, it will be readily apparent to those skilled in theart lthat this inventionprovides a combined electrical switch and variable resistor having a minimum v number of vcomp'onents which'can bey manufactured yat low cost and in such a way as to facilitate assembly in the instrumentality, and which are so designed as to enable them to be incorporated in aV truly miniaturized control without sacrificing electrical clearances or a long and useful life of the instrumentality.

What is claimed as our invention is:

l. In an electrical control instrumentality of the type comprising a combination switch and variable resistor: housing means for the instrumentality having side walls, spaced front and rear walls,. and an intermediate wall of insulating material with a centra-l bearing hole therein,A

said intermediate wall dividing the interior of the housing means into a rear compartment containing the variable resistor mechanism and a front compartment containing the yswitch mechanism; the switch mechanism including cooperating stationary and movable contacts mounted on said intermediate wall; the variable resistor mechanism including a contactor carrier rotatably supported in the bearing hole of said intermediate wall and having a switch actuating member thereon projecting forwardly into the switch cor ment" and cooperable with the movable switch contact Vtherein 5to control the switch in accordance with rotation of the contacter carrier, said carrier having an axial drive socket Ytherein opening forwardly to the switch compartment; the front wall of the housing means having an aperture therein aligning with said bearing hole;

Y and a rotatable operating shaft o n the instrumentality,

projecting rearwardly throughsaid aperture in the front wall into the switch compartment, the rear endportion of the operating shaft yextending into said drive socket in the carrier'and consti'tnting a driver bywhich rotation is transmitted from the shaft to the carrier. v

2. The electrical control instrumentality of claim l,V

further characterized'byz'the fact that said contactor carrier has a hub which proiects forwardly into the switch compartment and is provided with an elongated bore communicating with said drive socket and in which a portion of the operating shaft is received to be supportedV by the contactor carrier. Y Y y 3. The electrical control instrumentality of claim 2, wherein that portion of the operating` shaft which is received in the aperture in the front wall of the housing means has a circumferential groove therein, and wherein said aperture has a keyhole ,shape with the small end of the keyhole coaxial with said bearing hole and of a size to rotatably receive said grooved portion of the shaft so as to hold the shaft against axial motion relative to the housing means, the large end of the keyhole having a size great enough to enable the shaft to pass yen dwise therethrough; and further characterized by the provision of retaining means in the front of the switch compartment engaged with the shaft to prevent lateral motion of said grooved portion thereof out of the small end of the keyhole opening.

4. The electrical control instrumentality of claim 3, wherein said retaining means comprises a washer confined between the front ofthe hub on the carrier and the front wall of the housing means, said washer having a central hole to snugly but rotatably receive the operating shaft, and having its periphery contiguous to the side wall of the housing means and cooperable therewith to hold the washer, and hence the operating shaft, against lateral shifting out of the small portion of the keyhole shaped aperture in the front wall of the housingV means.

5. rl'he electrical control instrumentality of claim 4, further characterized by the fact that the Side wall of the housing means is cylindrical and has an indentation therein adjacent to its junction with the front wall; and further characterized by the fact that said washer has Ya notch in its peripheral portion in which said indentation is received to hold the washer against rotation with the operating shaft.

6 The electrical control instrumentality of claim 1, wherein the movable contact of the switch comprises a resilient spring blade having'an arcuate portion overlying said intermediate wall and substantially concentric to the axis of rotation of the contacter carrier, said arcuate portion having one end iixed to said intermediate `wall at one side of the switch compartment and having its free end portion at the opposite side of the switch V' 'cacimpartfment and yieldingly biased toward the intermediate wall; wherein the' '.Stafionary man is xs to' ist@ intermedi: atewall a'tfa location to be normally engaged by the free end of the movable contact; and wherein the switch actu-v ating member comprises a cam on the contacter carrier ext'ending axially therefrom for engagement with the movable switch contact to hold its free end exed forwardly and disengaged from the stationary contact in one position of rotation of the contactor carrier.V

7. In an electrical control instrumentality of the type comprising a combination switch and variable resistor: housing means for the instrumentality having spaced front and rear walls, and an intermediate wall of insulating material providing a switch base having a substantially large diameter bearing hole in its center, said intermediate wall dividing the interior of the housing means into a rear compartment containing the variable resistor mechanism and a front compartment containing the switch mechanism; the switch mechanism including a contactor blade having a resilient free end portion biased in one axial direction toward a switch closed position but capable of being iiexed in the opposite axial direction to a switch open position; the variable resistor mechanism including a rotatable contactor carrier of insulating material having a large diameter hub portion received in said bearing hole whereby the carrier is rotatably supported from the intermediate wall of the housing means, and having a smaller diameter hub portion projecting forwardly into the switch compartment, said smaller diameter hub portion having a switch actuating member thereon which is engageable with the contactor blade to hold the blade tiexed in a switch open position in one position of rotation of the carrier; and said variable resistor mechanism including stator elements fixed on the rear wall of the housing means, spring contact fingers on the rear of the rotatable carrier arranged to track upon said stator elements,l and means on the carrier providing a forwardly facing shoulder engaging the rear of said intermediate wall to hold the spring contact fingers engaged with the stator elements under spring tension; said smaller diameter hub portion having a bore therein opening forwardly into the switch compartment and leading rearwardly of the carrier to a drive socket in the large diameter hub portion; the front wall of the housing means having a shaft receiving aperture therein aligning with said bore in the carrier hub; and a rotatable operating shaft for the instrumentality, said shaft projecting rearwardly through said aperture in the front wall and extending into the'bore in the carrier to be supported on the instrumentality thereby, and the rear end portion of the shaft engaging in said drive socket and constituting a driver by which rotation is transmitted from the operating shaft to the carrier, the bottom of said drive socket being located rearwardly of the rear end of the operating shaft; and cooperating means on the shaft and the housing means for transmitting rearward end thrust on the shaft directly into the housing means so as to preclude the transmission of such thrust onto the contactor carrier.

8. In an electrical control instrumentality of the type comprising a combination switch and variable resistor: housing means for the instrumentality including front and rear-housing sections connected in end to end relation and each comprising a metal cup having its bottom facing forwardly, a rearwardly extending cylindrical side wall, and a rear wall of insulating material extending across and abutting the rim of the cup to be held thereby in spaced paraliel relation to the bottom of the cup, the rear wall of the front housing section being flatwise contiguous to the front wall of the rear housing section and being clamped between it and the rim of the front housing section by the end to end connection between the housing sections; said contiguous walls together providing a transverse intermediate wall of the housing means, and said intermediate wall having a substantially large diameter bearing hole therein; the bottom of the front housing section having an aperture therein coaxial with said bearing hole; switch mechanism in the front housing section including cooperating stationary and movable contacts mounted on the rear wall of said front housing section; variable resistor mechanism in the rear housing sec- 10 l tion including a contactor carrier having a hub which projects forwardly into said bearing hole to rotatably support the carrier from said intermediate wall; an operating shaft rotatably supported by the housing means and projecting rearwardly through the aperture in the bottom of the front housing section; and interengaging means on the carrier and the rear portion of the operating shaft providing a rotation transmitting connection between the shaft and the carrier.

9. In a combination electric switch and variable resistor: housing means having spaced apart substantially parallel front, rear and intermediate walls, the latter being of insulating material and providing a switch base which divides the interior of the housing means into a forwardly disposed switch compartment and a rearwardly disposed variable resistor compartment, said front and intermediate walls having aligning centrally located apertures therein; a rotatable operating shaft; means carried by the housing means constraining the shaft to rotation, with the shaft projecting rearwardly through said aperture in the front wall; a variable resistor in the rear compartment comprising cooperating rotor and stator assemblies, the stator assembly being mounted on the inner face of the rear wall, and the rotor assembly including a contact carrier having a portion rotatably journaled in the aperture of the intermediate wall and connected with the inner end portion of the operating shaft to be driven thereby; cooperating stationary and movable contacts carried by thek switch base; and means on the Contact carrier providing an actuator engageable with the movable switch contact to effect switch opening and closing motion of the movable contact with respect to the stationary contact as a consequence of rotation of the actuator with the operating shaft.

10. In a combination electric switch and variable resistor: housing means having spaced apart transverse end and intermediate walls, thedatter being of insulating material and providing a switch base which divides the interior of the housing means into axially adjacent switch and variable resistor compartments, one of said end walls and the intermediate wall having centrally disposed axially aligning holes therein; a rotatable operating shaft; shaft supporting means carried by the housing means and constraining the shaft to rotation with one end portion of the shaft projecting into the housing means through the hole in said one end wall; cooperating rotor and stator assemblies in the variable resistor compartment, respectively carried by the intermediate wall and the end wall bounding said resistor compartment, the rotor assembly being connected with the shaft to be driven thereby and having a portion which projects through the hole in the intermediate wall and into the switch compartment; cooperating rotation stops carried by the housing means and the rotor to define the limits of rotor rotation; switch mechanism in the switch compartment comprising a stationary contact mounted on said intermediate wall, and a movable contactor mounted on said intermediate wall and having a contact engaging portion movable back and forth axially of the operating shaft toward and from engagement with the stationary contact, said contactor being biased toward engagement with the stationary contact; and means on said rotor portion engageable with the contactor at one limit of rotation of the rotor for holding the contactor separated from the stationary contact, and for effecting engagement of the contactor with the stationary contact as a consequence of rotation of the rotor away from said one limit thereof.

ll. As an article of manufacture, a rotor assembly for a variable resistor, comprising: a contactor carrier molded of insulating material and having a disclike body portion, a hub projecting forwardly from one face of the body portion and comprised of axially adjacent inner, outer, and intermediate hub sections of large, small, and intermediate diameters, respectively, the intermediate hub section providing a rotor supporting journal, and said lil hub having a bore therein opening to the front of the small diameter hub section, for receiving and supporting an operating shaft; circumferentially spaced driving abutxnents in said bore engageable with similar abutments on an operating shaft having an end portion supported in the bore to provide for the transmission of rotation to the rotor; means on the side of said outer hub section adjacent to its junction with the intermediate hub section providing a switch operating cam; a pilot bearing on the body portion projecting from the other face thereof, coaxially of the rotor hub; and spring contact fingers mounted on said other face of the body portion.

12. As an article of manufacture, a rotor assembly for a variable resistor, comprising: a contactor carrier of insulating material having a disclike body and a hub projecting from the front face of the body to provide a bearing by which the rotor may be rotatably mounted in a support; driving lugs on the hub to connect the rotor with an `operating shaft for rotation with the latter; said disclilte body having a protuberance projecting from its rear face at a location a distance to one side of the rotor axis, and having a pair of notches in its periphery near said protuberance but located equal distances to opposite sides of a plane containing the rotor axis and passing through the protuberance; and a contactoi` stamped from resilient sheet metal and atwise overlying the rear Vface of the disclike body, said contactor having a body portion which is disposed wholly at said side of the rotor axis and has an aperture therein to receive and be located by said protuberance, and having securement tabs on outer edge portions thereof passing forwardly through the notches in the periphery of the disclike body of the rotor and bent over onto the front face of the body so as to cooperate with the protuberance in holding the contacter assembled with the rotor in a predetermined position thereon; and said contactor having a pair of opposing, oppositely curved outer spring fingers formed thereon, which fingers emanate from the body portion of the contactor adjacent to the securement tabs and ex tend in opposite angular directions, substantially concentric to the rotor axis, to the side of the rotor axis remote from said protuberance, the free end portions of said lingers being intersected by said plane and being spaced from one another radially of the rotor axis; and said contacter having an inner arcuate lfinger in spaced substantially concentric relation to one of said outer fingers, said inner linger emanating from the body portion at a location intermediate the bases of the outer fmgers and having its free end portion radially adjacent to the free end portion of said one linger and intersected by said plane; and the free end portions of all of said iingers being oiset outwardly and biased away from said other ace of the body portion of the carrier.

13. In an electrical control instrumentality: spaced apart substantially parallel walls and a side wall extending between and secured to said parallel walls to define a housing for a variable resistor, said parallel walls having coaxial bearing holes in their central portions, andv one of said walls being apertured alongside its bearing hole; variable resistor mechanism in said housing includ#- ing a rotor of insulating material having a disclike body with ioural means extending from the Opposite fasesthereof and rotatably received in said bearing holes -to support the rotor for rotation inthe housing, and a stator mounted on said apertured wall, concentric to the rotor axis,`and comprising a collector ring lying flatwise against said apertured wall and encircling the adjacent journal means, and an arcuate resistance element encircling the collector ring in radially spaced relation thereto; means on the rotor providing shoulders engaging the inner face of the collector ring and the other of said parallel walls to inhibit axial motion ot the rotor in the housing and to hold the collector ring against separation from said apertured wall; means on the collector ring engaged in the apertures of said apertured wall to preclude rotation of the ring with the rotor, said means including a terminal connected with the ring and projecting through one of said apertures to the exterior ofv the housing; and spring contactiingers on the rotor body riding upon the collector ring and the resistance element.

14. The electrical control instrumentality of claim 1 3, wherein said means on the collector ring which pref cludes rotation of the ring with the rotor includes locating tabs on the ring engaging in apertures in said apertured wall to hold the ring coaxial with the bearing hole in said apertured' wall; and wherein the hole in the collector ring is of a size to rotatably receive the journal means sur.- rounded by the ring whereby the ring cooperates with said parallel walls to rotatably support the rotor.

15. In an electrical control instrumentality: substantially parallel spaced apart walls and a side wall extend.- ing between and connected to said walls to define a housing for a variable resistor, one of said parallel walls having a main bearing hole in its center; variable resistor mechanism in said housing including a rotor of insulating material, and a stator mounted on the other of said parallel Walls, concentric to said bearing hole; the stator com,- prising an arcuate resistance element, and a collector ring encircled by the resistance element and having a hole in its center which provides a pilot bearing; cooperating locating means on the collector ring and on the adjacent one of said parallel walls for holding the collector ring against Shifting out of coaxial relation with said main bearing hole and for precluding rotation of the ring about its axis; journal means on the rotor rotatably received in said main and pilot bearing holes to support the rotor for rotation in the housing; means on the rotor providing shoulders engaging the inner face of the collector ring and said main bearing wall to inhibit axial motion of the rotor in the housing and to hold the collector ring against axial separation from the wall upon which it is mounted; and spring contact fingers on the rotor having pressure en gagement with the resistance element and the collector ring, to traverse the same when the rotor is rotated.

References Cited in the tile of this patent UNITED STATES PATENTS 2,791,666 Daily et al. May 7, 1957 2,855,490 Arisman et al. Oct. 7, 1958 FOREIGN PATENTS 960,213 Germany a--- Feb. 28, 1957 

